Device for extracting liquid from sludge

Abstract

A conveyor-type sludge filtering device for extracting the liquid component from the sludge, the device including a horizontally moving supported strand of a perforate endless conveyor belt onto which a continuous flow of sludge is deposited, while rows of flow breaker members extend downwardly into the moving sludge, thereby preventing the formation of sludge layers, especially of a belt-plugging bottom layer of solid matter. The flow breakers are preferably wedge-shaped and pivotably supported on transverse rods.

We claim the following: 
     
       1. In a device for extracting liquid from a suspension or sludge, the combination comprising: a continuously advancing endless perforate conveyor belt having a substantially horizontally extending belt strand;   a guide means for supporting the horizontal conveyor belt strand from the underneath, said guide means being pervious to liquid;   means for depositing onto the advancing conveyor belt strand a continuous bed of suspension or sludge;   walls for laterally retaining said suspension or sludge bed on the advancing conveyor belt strand, as its liquid component progressively passes downwardly through the belt and guide means; and   at least two successive rows of downwardly pointing flow breakers arranged above the horizontal conveyor belt strand so as to extend into the moving sludge bed, thereby disturbing the sludge flow and preventing the premature formation of a layer of solid material immediately above the conveyor belt strand; and wherein   each row of flow breakers is carried by a transversely extending supporting rod which is mounted in the lateral retaining walls;   the supporting rods and associated flow breakers define a transverse pivot axis for the flow brakers at a level above the normal level of the sludge; and   the flow breakers are subjected to an angular biasing force urging them into a normal operating position against the movement of the sludge bed on the conveyor.   
     
     
       2. A combination as defined in claim 1, wherein the flow breakers are upright elongated members of generally cylindrical shape. 
     
     
       3. A combination as defined in claim 1, wherein the flow breakers are elongated members facing the sludge flow with the leading edges which are inclined so that the lower member extremities are further upstream than the upper member extremities, thereby tending to raise solid matter, especially fibrous solid matter from the bottom layer of the flowing sludge to a higher flow level. 
     
     
       4. A combination as defined in claim 1, wherein the rows of flow breakers are laterally staggered so that the gaps between the members of one row are faced by flow breaker members of the next row. 
     
     
       5. A combination as defined in claim 1, wherein the flow breakers define a minimal vertical clearance between their lower extremities and the upper surface of the conveyor belt strand, when the breaker members are positioned in their lowermost pivotal position. 
     
     
       6. A combination as defined in claim 1, wherein the flow breakers are upright elongated members of wedge-shaped cross section which are so oriented that they present a pointed leading edge to the sludge flow. 
     
     
       7. A combination as defined in claim 6, wherein: each flow breaker has an upper supporting nose extending in the upstream direction from its leading edge;   said pivot axis with the supporting rod is located in said nose; and   each row of flow breakers further includes an abutment rod engaging the flow breakers of the row, so as to define their lowermost angular position against said angular biasing force, while permitting each member to be pivoted upwardly about said pivot axis, when it encounters an accumulation of solid matter in the sludge flow.